Hydraulic latch stinger

ABSTRACT

Disclosed herein is a releasable latching device for connecting a tubing string or conduit to a packer or other apparatus that is located in a well bore or the like. The latching device includes an elongated hollow body that has an upper end connected with the conduit and a lower end insertable into the apparatus that is located in the well bore. An annular or cylindrical member encircles the body and has a plurality of latching portions on the lower end thereof that are movable radially outwardly with respect to the body. A sleeve encircles the body between the cylinder member and body and includes a lower portion that is engageable with the latch portions to hold the latch portions in latching engagement with the apparatus. The sleeve is retained in engagement with the latch portions by hydraulic pressure within the conduit and within the cylinder. Movement of the sleeve out of engagement with the latch portion to be moved inwardly and out of the recess in the apparatus whereby the tubing string can be disconnected from the apparatus.

United States Patent [72] Inventor Andrew J.Tucker Mesquite, Tex. [21] AppLNo. 811,824 [22] Filed Apr. 1.1969 [45] Patented Feb. 2, 1971 [73] Assignee. Dresser lndustriesJnc.-

Dallas,Tex. a corporation of Delaware [54] HYDRAULIC LATCH STINGER 13 Claims, 7 Drawing Figs.

[52] U.S.Cl 166/114, 166/120 [51] lnt.Cl ..F21b33/l2. F21b23/00 [50] FieldoiSearch .7 166/114, 120.212

[56] References Cited UNITED STATES PATENTS 2,975,836 3/1961 Brown 166/217 3,011,558 12/1961 Conrad 166/212 3,391,740 7/1968 Edwards..lr. 166/120 3,399,729 9/1968 McGill 166/120 Primary Examiner-James A. Leppink AnameysRobert W. Mayer. Daniel Rubin, Roy L. Van

Winkle and William E. Johnson. Jr. a

ABSTRACT: Disclosed herein is a releasable latching device for connecting a tubing string or conduit to a packer or other apparatus that is located in a well bore or the like. The latching device includes an elongated hollow body that has an upper end connected with the conduit and a lower end insertable into the apparatus that is located in the well bore. An annular or cylindrical member encircles the body and has a plurality of latching portions on the lower end thereof that are movable radially outwardly with respect to the body.-A sleeve encircles the body between the cylinder member and body and includes a lower portion that is engageable with the latch portions to hold the latch portions in latching engagement with the apparatus. The sleeve is retained in engagement with the latch portions by hydraulic pressure within the conduit and within the cylinder. Movement of the sleeve out of engagement with the latch portion permits the latch portion to be moved inwardly and out of the recess in the apparatus whereby the tubing stnng can be disconnected from the apparatus.

HYDRAULIC LATCH STINGER BACKGROU ND OF THE INVENTION This invention relates generally to improved releasable latching devices for use in connecting a conduit or tubing string to a apparatus. such as a well packer. that is located in a well bore or the like. More particularly. but not by way of limitation, this invention relates to a releasable latching device that is pressure balanced whereby a differential pressure in the well bore cannot release the latching device.

In the past. many types of latching devices have been constructed that function to connect the tubing string with the packer that is located in a well bore. One of the most common types previously constructed includes a collet mechanism having a lower split end that is threaded on its exterior. The threaded portion is biased outwardly and is engageable with a mating thread formed in the packer. When the tubing string, with the collet attached, is lowered into the bore of the packer, the threads engage andratchet downwardly until the tubing string is connected with the well packer. Such devices can be released by exerting sufficient force upwardly on the tubing string to bias the collet ends inwardly and out of engagement with the thread in the packer bore.

As might be expected, such latching devices are susceptible to being inadvertently released upon the application of a differential pressure across the well packer. In view of this problem such latching devices have been constructed so that the tubing string must be rotated to unthread the mating threads to release the latching device.

One object of this invention is to provide an improved releasable latching device that can be connected and released without rotation.

Another object of the invention is to provide an improved releasable latching device that can be released by either a straight pull or by rotation.

A further object of the invention is to provide an improved releasable latching device that cannot be inadvertently released by fluid pressure.

The foregoing and additional objects and advantages of the invention will become more apparent as the following detailed description is read in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION This invention provides an improved releasable latching device for connecting a conduit to apparatus that is located in a well bore or the like wherein the apparatus is provided with latch receiving means. The latching device of this invention comprises: an elongated hollow body having an upper end arranged for connection with the conduit, a lower end insertable into the apparatus and having a pressure port extending through the wall of the body; a cylinder member encircling the body having a cavity therein in communication with the port; a latch member carried by the cylinder member and having at least one latch portion moveable radially with respect to said body, the latch portion being moveable into the latch receiving means and into engagement with the apparatus to connect the latching means to the apparatus; and, a piston encircling the body and located between the cylinder member and body. The piston includes an upper portion slidingly and sealingly engaging the cylinder member in the cavity and a lower portion engageable with the latch portion to hold the latch portion in the outward position. One of the cylinder member and piston being moveable on the body in response to pressure in the cavity whereby the lower portion of the piston engages the latch portion to lock the latch portion outwardly.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a view, partly in elevation and partly in cross section, illustrating a latching device constructed in accordance with the invention.

FIG. 2 is a view similar to FIG. 1, but showing the latching device in the latched position in a packer located in a well casing.

FIG. 3 is a view similar to FIG. I, but showing the various components of the latching device in the positions they occupy during retrieval of the latching device.

FIG. 4 is an enlarged cross-sectional view of a portion of the latching device illustrating, in more detail. the relationship between the latch portion of the device and the latch receiving means of the well packer.

FIG. 5 is a partial view illustrating a modification of the latching device shown in FIG. 1.

FIG. 6 is a view. partly in cross section and partly in elevation. of another embodiment of latching device that is also constructed in accordance with the invention.

FIG. 7 is a view similar to FIG. 5. but illustrating the latching device of FIG. 5 latched into a well packer located in a cased well bore.

DESCRIPTION OF THE EMBODIMENT OF FIG. 1

Referring to the drawing and to FIG. I in particular, shown therein and generally designated by the reference character 10 is a latching device constructed in accordance with the invention. The latching device 10 includes an elongated hollow body 12 that is threadedly connected at its upper end to the lower end of a tubing string or conduit 14.

The body 12 has a pressure port 16 extending therethrough near the upper end thereof. The lower end of the body 12 is enlarged and carries a plurality of seals 18 for purposes that will become more apparent as the description proceeds. Between the upper and lower ends of the body 12, the exterior thereof is relieved providing circumferentially spaced abutments 20 that extend upwardly between circumferentially spaced latch portions 22.

The upper ends of the latch portions 22 form an annular portion 24 that is threadedly connected to the lower end of a cylinder member 26. The latch portions 22 and annular portion 24 combined form a latch member that is designated by the reference character 28.

The latch member 28 is preferably constructed from a resilient metal so that the latch portions 22 are normally urged outwardly with respect to the body 12. The exteriors of the latch portions 22 are provided with threads 30 that will be described more fully hereinafter.

The cylinder member 26 slidingly encircles the body 12 forming an annular cavity 32 therewith. An O-ring seal 34 carried by the cylinder member 26 sealingly engages the body 12 and a setscrew 36 frictionally engages the exterior of the conduit l4 temporarily connecting the cylinder member 26 to the conduit 14 to prevent movement of the cylinder member 26 downwardly relative to the body 12. A lower end portion 38 of the cylinder member 26 extends downwardly over a portion of the latch member 28.

A sleeve 40 encircles the body 12 and is disposed between the body 12 and the cylinder member 26. An O-ring seal 42 carried by the sleeve 40 sealingly engages the exterior of the body 12 below the pressure port 16 and a seal 4-4 carried by the sleeve 40 sealingly engages the interior of the cylinder member 26 in the cavity 32. The upper end of the sleeve 40, in combination with the seals 42 and 44, forms a piston that is subject to the influence of pressure in the cavity 32 relatively above the upper end of the sleeve 40. The sleeve 40 also has a lower end 46 of reduced diameter that is arranged to be disposed between the interior of the latch portions 22 and the body 12 upon downward movement of the sleeve 40. When the lower end 46 is disposed between the latch portion 22 and the body 12, the latch portions 22 are prevented from moving toward the body 12.

A helical compression spring 48 is located in the cavity 32 and has its upper end in engagement with the sleevel'40 and its lower end in engagement with the cylinder 26. As :arranged, the spring 48 biases the sleeve 40 toward the position illustrated in FIG; 1 and against the force of pressure acting through the pressure port 16.

Referring to FIG. 2. the latching device 10 is illustrated therein as being disposed in latching engagement with a packer assembly 50 that has been previously set in a casing 52 that is located in a well bore (not shown). The packer 50 includes upper and lower slips 54 and 56. respectively, that are arranged to prevent movement of the packer 50 either upwardly or downwardly in the casing 52.

The packer 50 also includes a mandrel 58 that extends axially therethrough. The upper end of the mandrel 58 is provided with the threads 60 that are constructed to mate with the threads 30 on the latch portions 22.

FIG. 4 illustrates in more detail. the relationship of the threads 30 on the exterior of the latch portions 22 and the threads 60 formed in the upper end of the mandrel 58. As shown therein. the upper surfaces of the threads 60 and the lower surfaces of the threads 30 are disposed at a relatively large angle with respect to the horizontal so that the latch portions 22 will move downwardly past the threads 60 in a ratcheting manner. It will also be noted therein that the upper surfaces of the threads 30 and the lower surfaces of the threads 60 are disposed at a relatively flat angle compared to the horizontal so that considerably more force is required to move the latch portions 22 upwardly relative to the mandrel 58. However, and since there is an angle, the latch portions 22 can be disengaged from the mandrel 58 by an upward force of sufficient magnitude. For such movement to occur, the latch portions 22 must move inwardly toward the body 12. If the lower end 46 of the sleeve 40 is disposed as shown in FIG. 4, the latch portions 22 cannot move inwardly and the latch cannot be disengaged.

OPERATION OF THE EMBODIMENT OF FIG. l

When it is desired to latch the tubing string 14 into the packer 50, the latching device is threadedly connected with the lower end of the tubing string 14 and the setscrew 36 tightened to retain the cylinder member 26 in the position illustrated in FIG. 1. The tubing string 14 and the attached latching device 10 are then lowered through the casing 52 toward the packer 50 which has been previously set therein.

As the latch portions 22 enter the bore of the packer mandrel 58, the threads 30 on the latch portions 22 engage the threads 60 on the packer mandrel 58 ratcheting downwardly until the lower end 38 of the cylinder member 26 engages the upper end of the packer mandrel 58. As previously mentioned, the latch portions 22 are biased outwardly by the material forming the latch member 28 so that the threads 30 and 60 are in engagement as illustrated in FIGS. 2 and 4. Just prior to the entry of the latch portions 22 into the bore of the packer mandrel 58, the seals 18 carried on the lower end of the body 12 enter and sealingly engage the interior wall of the mandrel 58 preventing flow upwardly between the latching device 10 and the packer 50.

If the pressure in the casing 52 below the packer 50 is not greater than the pressure above the packer 50, the sleeve 40 remains in the position illustrated in FIG. 1 with the lower end 46 thereon out of engagement with the latch portions 22. With no pressure differential across the packer 50, the tubing string 14 and latching device 10 can be retrieved by exerting an upward pull thereon so that the latching portions 22 are biased inwardly out of engagement with'the threads 60 in the mandrel 58. Alternatively, and since the abutments 20 on the body 12 extend upwardly between the latch portions 22, the tubing string 14 and latching device 10 can be retrieved by rotating the tubing string 14 in a direction to unscrew the threads 30 from the threads 60.

If the pressure in the casing 52 is greater below the packer 50 than above, pressure through the port 16, exerts a force downwardly on the sleeve 40, driving the sleeve 40 downwardly until the lower end 46 is disposed between the latch portions 22 and the body 12 as shown in FIG. 2. As shown in FIG, 4, the latch portions 22 are held in engagement with the mandrel 58 and cannot move toward the body 12. Thus, the latching device 10 securely retains the conduit 14 attached to the packer 50 even in the presence of high differential in pressure across the packer 50. There will be no net force on the device 10 since the area of the body 12 affected by well pressure is equal to the area between seals 42 and 44.

To release the tubing string 14 and latching device 10 from the packer 50 in the presence of a differential in pressure, an upward pull is taken on the tubing string 14 bringing the upper ends of the abutments 20 into engagement with the lower end 46 of the sleeve 40. When this occurs. the lower end 46' of the sleeve 40 is moved from beneath the latch portions 22, continued movement of the tubing string 14 forces the latch portions 22 out of engagement with the mandrel 58.

If the cavity 32 becomes filled with debris or for other reasons the sleeve 40 cannot be moved upwardly, the tubing string 14 can be rotated, rotating the threads 30 on the latch portions 22 out of engagement with the threads 60 in the mandrel 58. Thus release of the latching device 10 from engagement with the packer 50 can be accomplished by straight pull or rotation of the tubing string 14. When the latching device 10 is fully released from the packer 50, the various components thereof will be disposed as illustrated in FIG. 3. The upward strain on the tubing string 14 with the latch portions 22 in engagement with the mandrel 58 causes the cylinder member 26 to slidedownwardly on the body 12. As soon as the seals 18 leave their sealing engagement with the mandrel 58, the pressure equalizes across the latching device 10 and the spring 48 drives the sleeve 40 upwardly to the position shown in FIG. 3.

If it is desired to reconnect the tubing string 14 with the packer 50, the latching device 10 can be lowered into the mandrel 58 as previously described. Since the cylinder member 26 has moved downwardly on the body 12, the tubing string 14 and body 12 will move downwardly relative to the cylinder member 26 after the lower end 38 thereon has engaged the upper end of the mandrel 58. This downward movement continues until the upper end of the cylinder member 26 engages the lower end of the tubing string 14. At this time, the various components of the latching device 10 are again in the positions illustrated in FIG. 2.

In the foregoing detailed description, it can be appreciated that the latching device 10 can be utilized to connect the tubing string 14 with the packer 50 and can be readily released therefrom even in the presence of relatively high differential existing across the packer 50. In most instances, the latching device 10 can be released from the packer 50 by a simple upward pull on the tubing string 14 without necessitating rotation between the tubing string 14 and the packer 50. It will also be appreciated that the latching device 10 cannot become inadvertently disengaged from the packer 50 due to the presence of higher pressure in the well bore below the packer 50 since the sleev40 moves downwardly under the influence of such pressure to securely hold the latch portions 22 in engagement with the mandrel 58.

DESCRIPTION or TI-IE MODIFICATIONS OF FIG. 5

Occasionally, it is desired to latch a tubing string into a packer that has been set in a well bore in order to perform processes in the well wherein considerable pressure is applied in the tubing string. Under such circumstances, the pressure may tend to shorten the tubing string and thus exert an upwardly directed force on the tubing string and the latching device. As previously mentioned, the latching device 10 can be disconnected by exerting an upward pull on the tubing string 14. To prevent inadvertent disengagement when such pressures are encountered the latching device 10 can be modified as illustrated i'n FIG. 5 wherein the modified latching device is designated by the reference character 100.

As shown therein, the latching device 10a includes many of the same components previously described in connection with the latching device 10. The same components are designated by the same reference characters. The body 12 has been modified and is designated therein by the reference character 12a.

To prevent inadvertent disconnection of the latching device 100 from the packer 50. the slots forming the abutments 2011 have been shortened to provide an upwardly facing shoulder 21 that is disposed in juxtaposition with the ends of the latching portions 22. As constructed. the shoulder 21 will engage the lower ends of the latching portions 22 preventing upward movement of the modified body 12a when an upward force is exerted on the tubing string 14. Since the body 12a cannot be moved upwardly a sufficient distance from the upper ends of the abutments 20a to engage the lower end 46 of the sleeve 40, the lower end 46 remains between the latching portions 22 and the body 12a and the threads 30 on the latching portions 22 cannot be moved inwardly out of engagement with the mating threads 60 in the mandrel 58. Thus, an upward pull of the tubing string cannot be utilized to disengage the latching device l0a from the packer 50.

When it is desired to remove the latching device a and the tubing string 14 from the well packer 50, the pressure within the body 12a is equalized, permitting the spring 48 to drive the sleeve 40 upwardly. The upward movement of the sleeve 40 moves the lower end 46 thereof from behind the latching portions 22. When this occurs, sufficient force exerted upwardly on the body 120 will cam the threads 30 inwardly away from the threads 60 as previously described thereby releasing the latching device 1011 from the packer 50.

In the event that there is not sufficient force developed by the spring 48 to move the sleeve 40 upwardly, pressure can be applied in the annular space between the tubing 14 and the casing 52. The pressure will act on the underside of the upper end of the sleeve 40 in the cavity 32 and drive the pistonlike sleeve 40 upwardly releasing the latching portions 22. When the sleeve 40 has been moved upwardly, the latching device 10a can be disconnected from the packer 50 by a straight upward pull on the tubing 14.

Since the short abutrnents 20a extend upwardly between the latching portions 22, the latching device 100 can also be released from the packer 50 by rotating the tubing 14 to unthread the thread 30 from the thread 60. Thus, the modified latching device 10a can be disconnected by a straight upward pull on the tubings string 14 after the sleeve 40 has been as previously mentioned, can be released by rotation.

DESCRIPT ION OF THE EMBODIMENT OF FIG. 6

FIG. 6 illustrates another embodiment of latching device that is generally designated by the reference character 100. The latching device 100 includes an elongated hollow body 102 that is threadedly connected at its upper end to the lower end of the tubing string 14.

The body 102 has a pressure port 104 extending therethrough near the upper end thereof. The body 102 is reduced in exterior diameter in its medial portion forming an upwardly facing shoulder 106. A plurality of spaced sealing rings 108 are carried on the lower end of the body 102.

Connected with the body 102 by lockrings 110 and 112 is a sleeve or piston 1 14. The sleeve 114 has a lower end 116 is in engagement with the upwardly facing surface 106 on the body 102.

The upper end of the sleeve 114 carries an O-ring seal 118 that is disposed in sealing engagement with the body 102 and an O-ring seal 120 that is disposed in sealing engagement with the interior of a cylinder member 122. The cylinder member 122 is slidingly disposed on the body 102 and carries an O-ring seal 124 in the upper end thereof that sealingly engages the body 102. The cylinder member 122, sleeve 114, body 102, and seals 119, 120 and 122 cooperate to form a chamber or cavity 125 that is in fluid communication with the port 104. At its lower end, the cylinder member 122 is threadedly connected to a cylindrical latch member 126.

The cylindrical latch member 126 includes an annular In each of the openings 132 there is located a latch portion or latch dog 134. The dogs 134 are moveable in the openings I32 toward and away from the body 102. A garter spring 136 is positioned around the exterior of the dogs 134 to bias the dogs I34 relatively toward the body 102.

A helical compression spring 138 encircles the sleeve 114 and has its upper end in engagement with the sleeve 114. The lower end of the spring 138 is in engagemenbwith the annular portion 128 of the latch member 126 so that the spring 138 biases the cylinder member 122 relatively downwardly toward the position illustrated in FIG. 6.

OPERATION OF THE EMBODIMENT OF FIG. 6

When it is desired to utilize the latching device to connect the tubing string 14 with the packer 50, which has been previously set in the casing 52, the tubing string 14 with the latching device 100 attached is lowered through the casing 52 toward the packer 50. The seals 108 carried on the lower end of the body 102 enter the bore of mandrel 58a preventing the flow of fluid between the mandrel 58a and the latching device 100. The downward movement of the tubing string 15 and latching device 100 continues until the downwardly facing shoulder 130 on the cylindrical latch member 126 engages the upper end of the mandrel 58a. At this time, the latch dogs 134 are retracted in the openings 132 in the latching device 100 as illustrated in FIG. 6, but are positioned adjacent an annular latch recess 60a located in the interior of the mandrel 580 as illustrated in FIG. 7.

It should be pointed out that the packer 50 is identical to that previously described in connection with the description-of FIG. 2 with the exception of a modification to the mandrel 58. As noted above, the modified mandrel is designated by the reference character 58a. The modification consists of forming the annular latch recess60a in the interior of the mandrel 58a in lieu of the threads 60 which were provided in the mandrel 58.

After engagement between the downwardly facing shoulder I30 and the upper end of the mandrel 58a, continued downward movement of the tubing string 14 moves the body 102 and the sleeve 114, which is attached to the body 102 downwardly. Since the cylinder member 122 is fixed by such engagement relative to the packer 50, farther downward movement of the sleeve 114 moves the reduced diameter end portion 116 downwardly relative to the latch dogs 134 until the larger diameter portion of the sleeve 114 is positioned behind the dogs 134.

The sleeve 1 14 engages the dogs 134 as it moves downwardly forcing the dogs 134 outwardly with respect to the body 102 and into the annular latch recess 60a. As can be appreciated from viewing FIG. 7, the latch dogs 134 are moved outwardly against the inwardly directed force exerted by the spring 136. With the dogs 134 positioned in the annular latch recess 600. the tubing string 14 and the latching device 100 are securely attached to the packer 50.

If the pressure in the casing 52 is greater below the packer 50 than above, the pressure acts through the port 104 exerting a pressure in the chamber 125 which produces a force in an upward direction against the cylinder 122 and in a downward direction against the sleeve 114. Since the area defined by the seals 1 18 and is equal to the area defined by the seals 108, the upward and downward forces will be of equal magnitude, an there will be no resultant force as a result of the pressure in the chamber 125. Thus, the latching device 100 will remain in the latched position regardless of the magnitude of the differential pressure existing in the casing 52. Also, there will be no net force on the device 100 since the area on the body 102 subject to well pressure is equal to the area defined by the seals 118 and 120.

f 3 To release the latching device 100 from the packer 50 an upward strain is taken on the tubing string 14 to raise the body 102 and the attached sleeve 114. Upward movement of the sleeve I14 returns the reduced diameter lower end 116 thereon to a position behind the latch dogs 134.

With the end 116 in this position, the spring 136 bisects the dogs 134 radially inwardly'toward the body 102 and out of the annular recess 60a in the mandrel 58a. Continued upward movement of the tubing string 14 then removes the latching device 100 from the packer 50.

It can be appreciated from the foregoing description that the latching device 100 is constructed and operates slightly differently from the latching device 10. However, it will also be noted that each of the latching devices described can be inserted and retrieved by linear movements of the tubing string 14. Furthermore, neither of the latching devices described can be inadvertently disengaged by a differential pressure existing across the packer 50.

The embodiments described in detail hereinbefore are presented by way of example only. it will be understood that many modifications and changes can be made thereto without departing from the spirit and scope of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

lclaim:

l. Releasable latching means for connecting a conduit to apparatus that is located in a well bore or the like, the apparatus being provided with latch receiving means, said latching means comprising:

an elongated hollow body having an upper end arranged for connection with the conduit, a lower end insertable into the apparatus and a pressure port extending through the wall of said body;

cylinder means encircling said body and having a cavity therein in communication with said port;

A latch member carried by said cylinder means and having at least one latch portion moveable radially with respect to said body, said latch portion being moveable into the latch receiving means and into engagement with the apparatus to connect said latching means to the apparatus; and

piston means encircling said body and located between said cylinder means and body, said piston means including an upper portion slidingly and sealingly engaging said cylinder means in said cavity and a second portion engageable with said latch portion to hold said latch portion in the outward position, one of said cylinder means and piston means being responsive to pressure in said cavity whereby said second portion is held in engagement with said latch portion.

2. The latching means of claim 1 wherein said latch member includes:

an annular portion; and

a plurality of said latch portions depending from and circumferentially spaced on said annular portion.

3. The latching means of claim 2 wherein said latch portions have a thread formed on the exterior thereof that engages a mating thread in the latch receiving means.

4. The latching means of claim 3 wherein said body includes a plurality of circumferentially spaced abutments located between said latch portions and engageable therewith whereby rotation of said body rotates said latch member.

5. The latching means of claim 4 wherein said body has an upwardly facing shoulder engaging the lower ends of said latch portions to prevent upward movement of said body relative to the apparatus when the pressure in said cavity is holding the second portion of said piston means in engagement with latch portions whereby said latching means cannot be disconnected by tubing shrinkage or the like.

6. The latching means of claim 5 and also including annular seal means carried by said body below said latch member, said seal means being arranged to sealingly engage the apparatus.

7. Releasable latching means for connecting a conduit to apparatus that is located in a well bore or the like, the apparatus being provided with latch receiving means, said latching means comprising:

an elongated hollow body having an upper end arranged for connection with the conduit, a lower end insertable into the apparatus and a pressure port extending through the wallofsaid body;

cylinder means encircling said body and having a cavity therein in communication with said port;

a latch member carried by said cylinder means and having at leastone latch portion moveable radially outwardly with respect to said body, said latch portion being moveable into the latch receiving means and into engagement with the apparatus to connect said latching means to the apparatus; and

piston means slidingly and sealingly encircling said body and located between said cylinder means and body, said piston means including an upper portion disposed in said cavity in sliding and sealing engagement with said cylinder means, said piston means being moveable in response to pressure in said cavity and also including a lower portion engaging said latch portion to hold said latch portion in the outward position when said piston means moves in response to pressure in said cavity. 8. The latching means of claim 7 and also including annular seal means carried by said body below said latch member, said seal means being arranged to sealingly engage the apparatus.

9. The latching means of claim 7 wherein: said latch member includes:

an annular portion connected to said cylinder means and having a plurality of circumferentially spaced openings extending therethrough, and I a plurality of said latch portions, one of said latch portions being disposed in a respective one of said openings, and

said latching means also includes an annular resilient member encircling said latch member in engagement with said latch portions to bias said latch portions toward said body.

10. The latching means of claim 7 wherein:

said latch member includes:

an annular portion connected to said cylinder means, and

a plurality of said latch portions circumferentially spaced and depending from said annular portion, and said body also includes a plurality of circumferentially spaced abutments located between and engageable with said latch portions whereby rotation of said body rotates said latch member.

11. Releasable latching means for connecting a conduit to apparatus that is located in a well bore or the like, the apparatus being provided with latch receiving means, said latching means comprising:

an elongated hollow body having an upper end arranged for connection with the conduit, a lower end insertable into the apparatus and a pressure port extending through the wall of said body;

cylinder means slidingly and sealingly encircling said body and having a cavity therein in communication with said port, said cylinder means being responsive to pressure in said cavity;

a latch member carried by said cylinder means and having at least one latch portion moveable radially outwardly with respect to said body, said latch portion being moveable into the latch receiving means and into engagement with the apparatus to connect said latching means; and

piston means mounted on and encircling said body between said cylinder means and body, said piston means including an upper portion disposed in said cavity in sealing engagement with said cylinder means and also including a second portion engaging said latch portion to hold said latch portion in the outward position when said cylinder means moves in response to pressure in said cavity.

12. The latching means of claim 11 wherein said latch member includes:

an annular portion attached to said cylinder means;

said annular portion having a plurality of circumferentially spaced openings extending therethrough, and

an annular portion connected to said cylinder means, and a plurality of said latch portions circumferentially spaced and depending from said annular portion. and said body also includes a plurality of circumfcrentially spaced abutments located between and engageable with said latch portions whereby rotation of said body rotates said latch member. 

1. Releasable latching means for connecting a conduit to apparatus that is located in a well bore or the like, the apparatus being provided with latch receiving means, said latching means comprising: an elongated hollow body having an upper end arranged for connection with the conduit, a lower end insertable into the apparatus and a pressure port extending through the wall of said body; cylinder means encircling said body and having a cavity therein in communication with said port; A latch member carried by said cylinder means and having at least one latch portion moveable radially with respect to said body, said latch portion being moVeable into the latch receiving means and into engagement with the apparatus to connect said latching means to the apparatus; and piston means encircling said body and located between said cylinder means and body, said piston means including an upper portion slidingly and sealingly engaging said cylinder means in said cavity and a second portion engageable with said latch portion to hold said latch portion in the outward position, one of said cylinder means and piston means being responsive to pressure in said cavity whereby said second portion is held in engagement with said latch portion.
 2. The latching means of claim 1 wherein said latch member includes: an annular portion; and a plurality of said latch portions depending from and circumferentially spaced on said annular portion.
 3. The latching means of claim 2 wherein said latch portions have a thread formed on the exterior thereof that engages a mating thread in the latch receiving means.
 4. The latching means of claim 3 wherein said body includes a plurality of circumferentially spaced abutments located between said latch portions and engageable therewith whereby rotation of said body rotates said latch member.
 5. The latching means of claim 4 wherein said body has an upwardly facing shoulder engaging the lower ends of said latch portions to prevent upward movement of said body relative to the apparatus when the pressure in said cavity is holding the second portion of said piston means in engagement with latch portions whereby said latching means cannot be disconnected by tubing shrinkage or the like.
 6. The latching means of claim 5 and also including annular seal means carried by said body below said latch member, said seal means being arranged to sealingly engage the apparatus.
 7. Releasable latching means for connecting a conduit to apparatus that is located in a well bore or the like, the apparatus being provided with latch receiving means, said latching means comprising: an elongated hollow body having an upper end arranged for connection with the conduit, a lower end insertable into the apparatus and a pressure port extending through the wall of said body; cylinder means encircling said body and having a cavity therein in communication with said port; a latch member carried by said cylinder means and having at least one latch portion moveable radially outwardly with respect to said body, said latch portion being moveable into the latch receiving means and into engagement with the apparatus to connect said latching means to the apparatus; and piston means slidingly and sealingly encircling said body and located between said cylinder means and body, said piston means including an upper portion disposed in said cavity in sliding and sealing engagement with said cylinder means, said piston means being moveable in response to pressure in said cavity and also including a lower portion engaging said latch portion to hold said latch portion in the outward position when said piston means moves in response to pressure in said cavity.
 8. The latching means of claim 7 and also including annular seal means carried by said body below said latch member, said seal means being arranged to sealingly engage the apparatus.
 9. The latching means of claim 7 wherein: said latch member includes: an annular portion connected to said cylinder means and having a plurality of circumferentially spaced openings extending therethrough, and a plurality of said latch portions, one of said latch portions being disposed in a respective one of said openings, and said latching means also includes an annular resilient member encircling said latch member in engagement with said latch portions to bias said latch portions toward said body.
 10. The latching means of claim 7 wherein: said latch member includes: an annular portion connected to said cylinder means, and a plurality of said latch portions circumferentially spaced and depending from said annular portIon, and said body also includes a plurality of circumferentially spaced abutments located between and engageable with said latch portions whereby rotation of said body rotates said latch member.
 11. Releasable latching means for connecting a conduit to apparatus that is located in a well bore or the like, the apparatus being provided with latch receiving means, said latching means comprising: an elongated hollow body having an upper end arranged for connection with the conduit, a lower end insertable into the apparatus and a pressure port extending through the wall of said body; cylinder means slidingly and sealingly encircling said body and having a cavity therein in communication with said port, said cylinder means being responsive to pressure in said cavity; a latch member carried by said cylinder means and having at least one latch portion moveable radially outwardly with respect to said body, said latch portion being moveable into the latch receiving means and into engagement with the apparatus to connect said latching means; and piston means mounted on and encircling said body between said cylinder means and body, said piston means including an upper portion disposed in said cavity in sealing engagement with said cylinder means and also including a second portion engaging said latch portion to hold said latch portion in the outward position when said cylinder means moves in response to pressure in said cavity.
 12. The latching means of claim 11 wherein said latch member includes: an annular portion attached to said cylinder means; said annular portion having a plurality of circumferentially spaced openings extending therethrough, and a plurality of said latch portions, one of said latch portions being moveably disposed in a respective one of said openings, and said latching means also includes an annular resilient member encircling said latch member in engagement with said latch portions to bias said latch portions toward said body.
 13. The latching means of claim 11 wherein: said latch member includes: an annular portion connected to said cylinder means, and a plurality of said latch portions circumferentially spaced and depending from said annular portion, and said body also includes a plurality of circumferentially spaced abutments located between and engageable with said latch portions whereby rotation of said body rotates said latch member. 